Logging headers added in a middleware - php

Question

I have a some GuzzleClientLoggingHandler which is as following:
class GuzzleClientLoggingHandler
{
/** #var HandlerStack */
private $handlerStack;
public function __construct(HandlerStack $handlerStack)
{
$this->handlerStack = $handlerStack;
}
public function log(): HandlerStack
{
$logger = Logger::getLogger(__CLASS__);
$middleware = Middleware::log($logger, $this->request());
$this->handlerStack->unshift($middleware);
$middleware = Middleware::log($logger, $this->response());
$this->handlerStack->unshift($middleware);
return $this->handlerStack;
}
}
and my client looks like:
new Client([
'base_uri' => 'https://example.com',
'handler' => (new GuzzleClientLoggingHandler($handlerStack))->log()
]);
and variable $handlerStack have n middleware, e.g.:
$handlerStack->unshift(new LanguageMiddleware());
in the middleware LanguageMiddleware I set a header for each request
public function __invoke(callable $handler)
{
return function (RequestInterface $request, array $options) use ($handler) {
$request = modify_request($request, [
'set_headers' => [
'Accept-Language' => Session::get('language')
]
]);
return $handler($request, $options);
};
}
And there is question: how to log this request with changed/setted headers?
Now all request modifications in a middleware doesn't appear in the logs.

Answer 1

You need to change order of middlewares in your stack. Take a look at the docs, there is a good explanation on how middlewares are applied to requests and responses (pay attention to the order!).
So to log requests with all the modifications applied you need to put you middleware in the end of the stack with ->push() instead of ->unshift().